Effects of structural and non-structural Al species on the stability of MCM-41 materials in boiling water

The mesoporous framework of MCM-41 is found in this study to be remarkably stabilized in boiling water for 1 week by simply substituting structural Al in the framework or introducing non-structural Al species onto the pore su rface of MCM-41. The enhancement of the stability of MCM-41 is found to be attributed to two major factors: The effect of randomness in pore structure (due to structural Al species in the framework) in enhancing the thermodyn amic stability of the mesostructural framework as well as the effect of the "protective surface composite layer" (due to the non-structural Al-species on the pore surface) in preventing the covered surface hydroxyl groups fro m hydrolysis with water molecules. (C) 2000 Elsevier Science B.V. All right s reserved.